Celestial Navigation - Apollo history - Solar System flights

tahanson43206 · 2023-12-22 10:09:46

For SpaceNut ... we had no topics with the words "celestial" and "navigation"

On Earth, Celestial Navigation has been used by sailor for many thousands of years, and by other creatures for millions of years.

Celestial Navigation was used to complete the Apollo Missions, and I expect it is still the major navigation method used for planning space flights today.

This topic is offered for those members who might wish to contribute to a collection of links and text to illuminate the subject for present and future readers.

During the Apollo missions, the navigator behind the Moon, out of communication with Earth, had to point the spacecraft precisely at a celestial object. That was a lot of responsibility, and every one of the navigators on the missions carried out that responsibility accurately.

This topic will open with a vision of a collection of data/information that may not exist at present.

In later posts, we have the opportunity to find and point to repositories of information about flight planning for current missions, whether it be to the Moon, Mars or any other Solar System objectives.

I expect we will find that in each and EVERY case, a star sighting is required before ANY burn is initiated. The sole exception may be orbital maneuvers, which may be restricted to the three bodies in play ... the mass around which the space craft is orbiting, the vehicle itself, and the target, which may be another vehicle, an object of interest, or just a position that is advantageous for some reason.

The skyscape as seen from Earth is available for anyone with Internet access, at theskylive.com. That web site is the source of position data for Mars as posted in the daily Calendar update.

(th)

tahanson43206 · 2023-12-22 10:18:15

This is a vision statement. To the best of my knowledge (admittedly limited) no such repository exists.

Every single engine burn of the Apollo missions was performed when the space vehicle was pointing at a star, with the sole exception of burns performed to achieve in-orbit docking, and even there, the celestial background would have been visible as a reference.

It is possible that documentation of the computations performed to select a star for each burn are still available, but whether those documents can be found is a question. The Apollo missions took place in a time before computers were advanced enough for reliable service. John Glenn famously accepted a computer computation of a flight plan only if it matched the work done by the female computers he had relied upon previously.

The Apollo flight plans and related celestial navigation computations, would be (could be) a useful reference for future space craft navigators.

It is possible that there are books written to document those missions, and many others that have take place, before and since.

In today's Universe, automated navigation systems perform the pointing duties, but they still depend upon identification of a particular star (or perhaps set of stars) ahead of each burn.

(th)